Objectives The effect of non-self-similar hierarchy on the fracture mechanical properties of the biocomposite was identified, It is expected that the findings of this study could direct the path for designing bioinspired materials with superior mechanical properties. Method sthe numerical models were established with Abaqus, and the extended finite element method was used to simulate crack initiation and propagation in the biocomposite. The inclination angles θ with the axis of the platelet and prism of 0, 20_^o, 40_^o, 60_^o, 80_^o, 90_^oare considered in this study. Results The inclination angle θ had limited influence on stiffness of biocomposite when , while stiffness of biocomposite decreased with θ when θ>40_^o. The ultimate tensile strain also increased with θ when θ>40_^o. Asymmetry was also found in that the crack propagated in matrix surround the platelets when θ>0_^o. It is found that the crack propagatation on one side of the long axis of the mineral crystal is easier than that on the other side when θ>0_^o. Conclusions The non-uniform distribution of cracks was found in biological hard tissues arised from non-self-similar hierarchy. The non-uniform crystal arrangement in biocomposite resulted in local damage rather than catastrophic fracture. The finding of this study could shed new light on material design principles.